Changed my o2 today and it got rid of the 2c9e code but still have the 29dc cylinder injection switch off code and no improvement in driveability. I am starting to think its a lpfp or hpfp problem with either a sensor or a pump.

Not true, the JB4 just auto-clears any codes that come up. BMS does sell an O2 simulator that you can use to fool the ecu (and any OBDII tests) into thinking everything is ok and you can use it with the JB4.

"The JB4 tuning system includes this functionality built in so a DPFIX is not required if you are already running a JB4 Performance Tuner!"

Checked today. Black cable is in the front DP and gray is on the rear. The black is the longer of the two as per Penske parts and RealOEM. I followed the black and it is indeed the one that travels a few inches longer to the connector on the driver side of the motor. This confirms they are installed correctly.

I've been having this issue for some time now and I am in dire need of suggestions. I had JB4 installed and running well for several months on map 1. I installed VRSF catless DP's and began to run map 2. It ran perfectly for a few weeks, then I started to get codes, "service engine soon" light and sometimes "limp mode." Also, sometimes the car seems to stutter, as in jerk back and forth slightly as I am casually driving down the road. After it starts to act up, it is much more likely to continue to act up (After I clear the codes, it tends to run well for a while). Part of this includes a weird idle, it will randomly climb and then slowly fall back in place, sometimes rather roughly. I tried using map 2 and taking it easy, but still have issues. I ran map 1, same problem. I tried leaving it on stock map and it seems to be less likely to act up but still had the "service engine soon" light the other day just driving down the highway. I've replaced both pre-cat o2 sensors and the hpfp within the last month because I was getting those codes. I am still getting the same codes. One of the problems is that it doesn't always happen, some days it will be fine. I took it to BMW because finally the problem seemed to be occurring on stock map, leading me to think it was a hardware issue and not a tuning issue. I asked them to test my fuel pressure regulator because I was thinking it may be running rich. They said its within spec at 5.5 bar. Also, they blame it on the JB4.

The most likely situation in which limp mode occurs (big check engine light comes on and cuts all power) is when I wind out 3rd or 4th, not 2nd.

I am so frustrated and basically out of ideas... Anybody have any suggestions? :

Quote:

Originally Posted by phrenetiK

i threw these codes when my diverter valves were leaking. no idea why.

Quote:

Originally Posted by phrenetiK

converted my diverter valves to blow off valves, when i did that i could hear them leaking the entire RPM band.

Hey guys, think I've resolved the issue.

I haven't had a chance to drive my car too much lately due to work commitments but I gave it a few bursts the other night when I was out. After a few WOT I hear a noise from the engine bay, sounds like a major leak and can't build boost up. Fortunately I was only half a km from home so I drove sedately for the rest of the way. Got home and realised my charge pipe had popped off.

I have an ER charge pipe and it popped off at the intercooler connection as the rubber sleeve had come off the IC pipe entirely. I'm not sure if this has been loose for some time and it finally gave way, or if the mechanic forgot to nip up the clamps during my last service as he was working in that area. I tightened everything up now.

The reason I bring this up is since I've put it back together properly my codes have disappeared altogether. I have the P3 boost gauge and before these codes would flash up every time I started the car, which was a constant reminder. Since fixing this leak the codes have stopped appearing without me deleting them. I'm yet to hook up the BT tool but so far it looks promising.

So phrenetiK is correct. I recommend checking your charge pipe for leaks, especially if you have an aftermarket one. Not sure why this would cause exhaust codes but it did in my case. Very happy that I can finally put this behind me.